1. Field of the Invention
The present invention relates to a telephone answering device which facilitates the remote controlled playback of recorded incoming messages.
2. Description of the Prior Art
Telephone answering devices automatically answer an incoming telephone call. Generally they include a ring detector which turns on the device in response to a ringing signal. An outgoing announcement, typically pre-recorded on a magnetic tape loop, is transmitted to the telephone line. This announcement may say that the user is not in, and request the caller to leave a message which will be recorded automatically. At the end of the outgoing announcement, the device is switched to a mode in which the incoming messages are recorded on a magnetic tape. When this recording is complete, the device shuts off automatically and returns to a stand-by condition in readiness to receive the next call. Such devices are typified by the inventor's U.S. Pat. Nos. 3,780,226 and 3,909,537.
In these devices, the user must return to the instrument to play back the recorded incoming messages. This is accomplished by first depressing a rewind button which mechanically conditions the device to rewind the incoming message tape. Next, a playback button is depressed which starts the tape in the forward direction, and turns on appropriate circuitry to play back the recorded messages via a loudspeaker contained in the instrument.
It is desirable to permit the user to recover the recorded incoming messages without having to return to the location of the answering device. An object of the present invention is to provide a telephone answering apparatus which facilitates such remote controlled operation. With the present invention, the user need only call his own telephone number from any telephone. After he hears the outgoing announcement, the user transmits a "beep" tone from a small oscillator that is held against the telephone handset microphone. The telephone answering device recognizes this specific "beep" tone, and switches to the automatic playback mode. The tape is rewound, and the recorded messages are then played back over the telephone line to the user. When all of the messages have been played out, the instrument resets itself to the answering mode, and shuts down in readiness to receive the next call.
To accomplish such remote controlled playback, the answering device must include certain facilities. These include: (a) circuitry to detect only the specific "beep" tone, (b) an indicator that "remembers" the number or time duration of the recorded messages, (c) means for rewinding the message tape, (d) means for then advancing the tape in the forward direction and conditioning the circuitry to transmit the recorded messages over the telephone line, and (e) means cooperating with the indicator to terminate the playback operation when all of the messages have been played out. It is a further object of the present invention to provide all of these facilities.
Another object of the present invention is to provide voice controlled timing of the incoming message record cycle. Thus, instead of requiring a fixed time for the recording of an incoming message, the inventive answering device will continue to record so long as uninterrupted speech is received.
Another object of the present invention is to provide an improved ring detector circuit.